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Three Part Question

IN [adults with hamstring muscle injuries]
IS [eccentric loading or lumbopelvic control retraining]
BETTER AT [improving return to sport].

Clinical Scenario

A 24 year old professional football player presents with a hamstring strain grade 1-2 to the long head of biceps femoris. You have heard from a colleague who works in sports medicine that eccentric loading can be used as an alternative to lumbopelvic movement control retraining. Therefore, to try and improve function and reduce recovery time, you wonder if it should form part of your management plan.

Search Strategy

MEDLINE (1966-05/2015), CINAHL (1982-05/2015), AMED (1985 – 05/2015) and SPORTDiscus (1830 – 05/2015) and EMBASE (1996 – 05/2015) databases were searched using the OVID interface.
The Cochrane Library was also searched using keywords: Hamstring injuries AND rehabilitation

All searches were limited to human AND English language.

1. Hamstring rehabilitation
2. Biceps femoris.
3. Semitendinosus
4. Semimembranosus
5. 1 or 2 or 3
6. Nordic curls
7. Eccentric Loading
8. 6 or 7
9. 5 AND 8
10. Lumbopelvic control
11. Lumbar pelvic dysfunction
12. Lumbopelvic stabilisation
13. 10 or 11 or 12
14. 5 and 8 and 13.

Search Outcome

Five papers were found which were relevant to the three part question. One of which was a Cochrane systematic review with a last search date of 2012. This contained the paper by Sherry & Best (2004) which was separately scored for this BET due to its high relevance. The three other randomised controlled trial papers were published since the latest Cochrane systematic review.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Sherry, MA. Best, TA 2004 USA	N= 24 athletes with acute hamstring strains.	clinical parallel trial	1.Number of days until return to sport	1.No significant difference	Small sample size. No blinding of patients, therapists or assessors. No intention to treat analysis. Allocation risk unclear in paper. Clarified in Cochrane review (Mason et al 2012) that allocation was concealed and so is 'low risk'. No pain or participant satisfaction outcomes. No Ultrasound imaging scan or MRI used for diagnosis.
			2.Injury recurrence within the first 2 weeks	2.Group 1 had significantly greater re-injury with 6 athletes (54.4%) P=0.003. None in Group 2
			3.Injury recurrence within 1 year.	3.Group 1 had significantly greater re-injury with 7 athletes (70%) P=0.005. 1 athlete in Group 2 (7.7%).
			4.Lower-extremity functional evaluation.	4.No significant difference
Mason 2012 UK	2 RCT studies. N=104 subjects with acute hamstring injury	Systematic review 1a	1.Return to full pre injury function within 3 months.	1.One study showed that the experimental groups returned significantly quicker than the control groups. The other study did not.	Small number of studies with differing experimental interventions, therefore, no pooling of data or meta-analysis.
			2.Pain scale & patient satisfaction at discharge and follow up.	2.No data available in 2 studies.
			3.Number of treatments before discharge	3. No data for total number of treatments
			4.Re-injuries rates at 12 months	4. 1 study showed Group 1 had significantly greater re-injury with 7 athletes (70%) P=0.005. 1 athlete in Group 2 (7.7%). There are no other data available.
Askling et al. 2013 Sweden	N=56 Swedish elite sprinters and jumpers with acute hamstring injury, verified by MRI. Group 1 emphasis was on extensive lengthening, mainly during the eccentric muscle action (N=28). Group 2 conventional exercises with less emphasis on lengthening (N=28). Both groups had 3 exercises with aims to a) increase flexibility, b)strength and trunk stabilisation & c) specific strengthening	Randomised Clinical Trial	1.Number of days to return to full training	1.Significantly shorter in group 1 (P<0.001) mean 28 days (SD 8-58 days) versus 51 days (SD 12-94 days).	Allocation was not concealed. No blinding of patients, therapists or assessors. No intention to treat analysis. In addition, 11 players with clinical signs of acute hamstring injury, but where the MRI showed no sign of injury, were followed in parallel.
			2.Re-injuries were registered during a period of 12 months after returning to training.	2.Not statistically significant.
Silder et al. 2013 USA	N=31 athletes from sports that required high speed running with suspected acute hamstring injuries within the period of 10 days. Group 1 (N=16) progressive agility and trunk stabilisation programme. Group 2 (N=13) progressive running and eccentric strengthening. Both groups went through 3 rehabilitation phases with pre and post MRI scan.	randomised clinical parallel trial	1.Number of days to return to full training.	1.Not statistically significant. (NSS) between groups	Small sample size. No therapist blinding. No baseline data. 12 athletes indicated that they did not feel as if they had returned to pre-injury levels of performance satisfaction.
			2.Craniocaudal length of injury, as measured on MRI, accounting for more than one muscle.	2.NSS between groups
			3.Re-injuries were registered during a period of 12 months after discharge from rehabilitation.	3. NSS betwen groups
			4.Initial longer Craniocaudal length of injury as measured on MRI delays return to sport.	4.Initial Craniocaudal length was significantly associated with a longer time to return to sport (P=0.04).
Askling et al. 2014 Sweden	N=56 Swedish elite sprinters and jumpers with acute hamstring injury, verified by MRI. Group 1 emphasis was on extensive lengthening, mainly during the eccentric muscle action (N=28). Group 2 conventional exercises with less emphasis on lengthening (N=28). Both groups had 3 exercises with aims to a) increase flexibility, b)strength and trunk stabilisation & c) specific strengthening	randomised clinical parallel trial	1.Number of days to return to full training	1.Significantly shorter in group 1 (P<0.001) mean 49 days (SD 18-107 days) versus 86 days (SD 26-140 days).	Allocation was not concealed. No blinding of patients, therapists and assessors. No intention to treat analysis.
			2.Re-injuries were registered during a period of 12 months after return to training.	2.NSS between groups

Comment(s)

Sherry & Best (2004) showed that combining progressive agility and trunk stabilisation exercises would significantly reduce re-injury rates within 12 months after returning to sport. Mason et al's Cochrane review (2012) suggests that by using increased frequency of daily stretching (four times a day compared to once) accelerates the rehabilitation process. One paper (Silder et al. 2013) showed that when using follow-up MRI scans there was a significant delay in recovery when measuring cranio-caudal length in the eccentric strengthening approach. Two studies by Askling et al. (2013 & 2014), found that patients who underwent extensive lengthening, using eccentric muscle actions, trunk stabilisation and increasing flexibility exercises, significantly reduce the number of days until return to sport.

Clinical Bottom Line

The best available evidence suggests that in acute hamstring strains there is no difference between eccentric loading and lumbopelvic control as measured by time to return to sport or re-injury rates within 12 months. Combining both approaches may improve results but needs further study

References

1. Sherry, MA. Best, TA A comparison of 2 rehabilitation programs in the treatment of acute hamstring strains. Journal of Orthopaedic & Sports Physical Therapy 2004; Vol.34, No.3:116-125.
2. Mason DL, Dickens VA, Vail A. Rehabilitation for hamstring injuries. Cochrane Database of Systematic Reviews 2012. Issue 12. Art. No.:CD004575. DOI:10.1002/14651858
3. Askling CM. Tengvar M, Thorstensson A. Acute hamstring injuries in Swedish elite football: a prospective randomised controlled clinical trial comparing two rehabilitation protocols. British Journal of Sports Medicine 2013; Vol 47: 953-959.
4. Silder A, Sherry MA, Sanfilippo J, Tuite MJ, Hetzel SJ, Heiderscheit BC. Clinical and morphological changes following 2 rehabilitation programs for acute hamstring strains injuries: A randomized clinical trial. Journal of Orthopaedic & Sports Physical Therapy 2013; Vol.43, No.5:284-299.
5. Askling, CM., Tengvar, M., Thorstensson,A. Acute hamstring injuries in Swedish elite sprinters and jumpers: a prospective randomised controlled clinical trial comparing two rehabilitation protocols. British Journal of Sports Medicine 2014; Vol 48: 532-539.